diff --git a/lib/marv-rdf-driver.js b/lib/marv-rdf-driver.js
index ec978c1..024c1a6 100644
--- a/lib/marv-rdf-driver.js
+++ b/lib/marv-rdf-driver.js
@@ -60,6 +60,13 @@ module.exports = (options) => {
     const errors = validate.errors;
     const instancePath = errors[0].instancePath || 'migration script';
     switch (errors[0].keyword) {
+      case 'type': {
+        const fault = errors[0].message
+          .replace(/be object/, 'be an object')
+          .replace(/be array/, 'be an array')
+        message = `${instancePath} ${fault}`
+        break;
+      }
       case 'required': {
         const conjunction = errors.find(e => e.keyword === 'anyOf') ? 'and' : 'or'
         const missingProperties = errors.filter(e => e.keyword === 'required')
@@ -71,11 +78,12 @@ module.exports = (options) => {
           : `${instancePath} must have required ${missingProperties.length === 1 ? 'property' : 'properties'} ${missingProperties}`;
         break;
       }
+      case 'enum': {
+        message = `${instancePath} ${errors[0].message}: ${errors[0].params.allowedValues.join(', ')}`
+        break;
+      }
       default: {
-        fault = errors[0].message
-          .replace(/be object/, 'be an object')
-          .replace(/be array/, 'be an array')
-        message = `${instancePath} ${fault}`;
+        message = `${instancePath} ${errors[0].message}`
         break;
       }
     }
diff --git a/lib/schema.json b/lib/schema.json
index 5ed3c81..8da6c06 100644
--- a/lib/schema.json
+++ b/lib/schema.json
@@ -284,6 +284,5 @@
         ]
       }
     }
-  },
-  "required": []
+  }
 }
\ No newline at end of file
diff --git a/test/dsl.test.js b/test/dsl.test.js
index d26b6f7..9a8344c 100644
--- a/test/dsl.test.js
+++ b/test/dsl.test.js
@@ -274,7 +274,7 @@ describe('DSL', () => {
           - name: type
             type: TEXT
       `), (err) => {
-        match(err.message, new RegExp("/define_entities/0 must have required property 'identified by' or 'identified_by'"));
+        match(err.message, new RegExp("/define_entities/0 must have X required property 'identified by' or 'identified_by'"));
         return true;
       });
 
@@ -290,10 +290,139 @@ describe('DSL', () => {
         match(err.message, new RegExp("/define_entities/0/identified_by must be an array"));
         return true;
       });
-
-    });
+    }, { exclusive: true });
   });
 
+  describe('Change Sets', () => {
+    it('should require an effective from date', async (t) => {
+      await rejects(() => apply(t.name, `
+        add change set:
+          - frames:
+          - entity: VAT Rate
+            version: 1
+            action: POST
+            data:
+            - type: standard
+              rate: 0.10
+      `), (err) => {
+        match(err.message, new RegExp("/add_change_set/0 must have required property 'effective from' or 'effective_from'"));
+        return true;
+      })
+    })
+
+    it('should require at least one frame', async (t) => {
+      await rejects(() => apply(t.name, `
+        add change set:
+        - effective from: 2020-04-05T00:00:00.000Z
+      `), (err) => {
+        match(err.message, new RegExp("/add_change_set/0 must have required property 'frames'"));
+        return true;
+      })
+
+      await rejects(() => apply(t.name, `
+        add change set:
+        - effective from: 2020-04-05T00:00:00.000Z
+          frames:
+      `), (err) => {
+        match(err.message, new RegExp("/add_change_set/0/frames must be an array"));
+        return true;
+      })
+
+    })
+
+    it('should require frames to specify an entity name', async (t) => {
+      await rejects(() => apply(t.name, `
+        add change set:
+        - effective from: 2020-04-05T00:00:00.000Z
+          frames:
+          - version: 1
+            action: POST
+            data:
+            - type: standard
+              rate: 0.10
+      `), (err) => {
+        match(err.message, new RegExp("/add_change_set/0/frames/0 must have required property 'entity'"));
+        return true;
+      })
+    })
+
+    it('should require frames to specify an entity version', async (t) => {
+      await rejects(() => apply(t.name, `
+        add change set:
+        - effective from: 2020-04-05T00:00:00.000Z
+          frames:
+          - entity: VAT Rate
+            action: POST
+            data:
+            - type: standard
+              rate: 0.10
+      `), (err) => {
+        match(err.message, new RegExp("/add_change_set/0/frames/0 must have required property 'version'"));
+        return true;
+      })
+    })
+
+    it('should require frames to specify an valid action', async (t) => {
+      await rejects(() => apply(t.name, `
+        add change set:
+        - effective from: 2020-04-05T00:00:00.000Z
+          frames:
+          - entity: VAT Rate
+            version: 1
+            data:
+            - type: standard
+              rate: 0.10
+      `), (err) => {
+        match(err.message, new RegExp("/add_change_set/0/frames/0 must have required property 'action'"));
+        return true;
+      })
+
+      await rejects(() => apply(t.name, `
+        add change set:
+        - effective from: 2020-04-05T00:00:00.000Z
+          frames:
+          - entity: VAT Rate
+            version: 1
+            action: MEH
+            data:
+            - type: standard
+              rate: 0.10
+      `), (err) => {
+        match(err.message, new RegExp("/add_change_set/0/frames/0/action must be equal to one of the allowed values: POST, DELETE"));
+        return true;
+      })
+    })
+
+    it('should require frame data to specify at least one value', async (t) => {
+      await rejects(() => apply(t.name, `
+        add change set:
+        - effective from: 2020-04-05T00:00:00.000Z
+          frames:
+          - entity: VAT Rate
+            version: 1
+            action: POST
+      `), (err) => {
+        match(err.message, new RegExp("/add_change_set/0/frames/0 must have required property 'data'"));
+        return true;
+      })
+    })
+
+    it('should require frame data to specify at least one value', async (t) => {
+      await rejects(() => apply(t.name, `
+        add change set:
+        - effective from: 2020-04-05T00:00:00.000Z
+          frames:
+          - entity: VAT Rate
+            version: 1
+            action: POST
+            data:
+      `), (err) => {
+        match(err.message, new RegExp("/add_change_set/0/frames/0/data must be an array"));
+        return true;
+      })
+    })
+  })
+
   describe('Aggregates', () => {
     it('should aggregate data frames up to the specified change set', async (t) => {
       await apply(t.name, `